I don't necessarily believe this but I consider it an interesting plot, the idea that the nuclear arms race was actually about defending the planet against an alien invasion, that this is why the US and soviets never really physically beefed with each other and both countries pushed a bunch of propaganda on their people to make sure everyone sees it as a human war, but secretly humans needed the ability to annihilate all life on earth within seconds and make it uninhabitable, to discourage an invasion, ie "if you try to take us over we will wipe out everything and ruin the planet so you can't have it" so at this point any hypothetical aliens would have to successfully sabotage the nuclear defense system of countries all over the world and in quick order, it very loosely lines up with some predictive programming like superman, who is technically an alien, getting rid of all the nukes in the world by throwing them into the far reaches of space, anyway just an interesting plot idea